- Cohort 2: (16 patients: 8 KRAS wild-type (WT) and 8 KRAS Mutant(MT). Patients who have score of less than 4 by the OSI-906 integrated classifier will have OSI-906 added to irinotecan on disease progression to irinotecan (patients that are KRAS WT will have received cetuximab with irinotecan). Patients who are treated in the dose escalation phase at the recommended phase II dose of the combination and meet the criteria for Cohort 2 of the expanded phase may be counted towards the dose expansion patient numbers.